Hey all,
We have a known bug for Avast Secure Browser Mac, on the latest version of MacOS 10.15, the browser gives an error when installing.
This will only occur if you do a clean install on MacOS Catalina, if you already have the browser and you update your OS from Mojave you will be unaffected.
We are investigating this at the moment, something that needs to be fixed before we move out of beta.
Thanks